From Nytimes.com: Carbon trading, also known as cap and trade, has suffered a lot of hiccups in Europe over the past five years. Conceived to make it more expensive to emit greenhouse gases, the fledgling system in the European Union has been rocked by extreme volatility, cyber- attacks, tax fraud, recycling of used credits and suspicions of profiteering.
Despite those difficulties, carbon trading has developed into a business worth about $140 billion annually. While most of that business is concentrated in Europe, Asian nations are rolling out systems and Australia and the United States are still considering using trading as a tool for cutting carbon in the future...........................................Full Article: Source